Adjustable self-centering means for rotatable shafts



Dec. 5, 1967 M. LEVINE 3,356,357

ADJUSTABLE SELF-CENTEBING MEANS FOR P-OTATABLE SHAFTS Filed Dec. 28,1965 MARVIN l Lfl/l/VE 5W1 MM INVENTOR.

United States Patent 3,356,357 ADJUSTABLE SELF-CENTERING MEANS F ORROTATABLE SHAFTS Marvin I. Levine, Carle Place, N .Y., assignor toOptornechanisms, Inc., Plainview, N.Y. Filed Dec. 28, 1965, Ser. No.516,871 3 Claims. (U. 267-1) This invention relates to adjutableself-centering means for rotatable shafts and more particularly to suchmeans for control shafts which are rotated a fraction of a revolution.

The present invention is directed to means for restoring to neutralposition control shafts of the type which are used in instruments orvehicles for actuating control switches or valves.

Such devices of the prior art, are generally complicated and expensive,and do not have easily adjustable selfcenteriing means.

The present invention provides a simple reliable and inexpensivemechanism for self-centering a shaft to a neutral position withadjustable stop means.

Accordingly, a principal object of the invention is to provide new andimproved adjustable self-centering means for rotatable shafts.

Another object of the invention is to provide new and improved easilyadjustable self-centering means for rotatable control shafts.

Another object of the invention is to provide new and improvedself-centering means for rotatable control shafts of the type which arerotated a fraction of a revolution.

Another object of the invention is to provide new and improvedadjustable self-centering means for a shaft rotatably mounted in a framecomprising, a pair of members fixedly connected to and spacedfrom saidshaft, a spring mounted on said shaft adjacent said members, a pair ofadjustable stops mounted in said frame and equally spaced outwardly ofsaid members, the ends of said springs extending outwardly past saidmembers and adapted to come into contact with said adjustable stops whensaid shaft is in neutral position so that when said shaft is rotated ineither direction, one end portion of said spring will bear against oneof said members in a direction to restore said shaft to neutralposition, said neutral position being determined by the position of saidadjustment stops.

These and other objects of the invention will be apparent from thefollowing specification and drawings of which:

FIGURE 1 is a side view of the embodiment of the invention.

FIGURE 2 is a bottom view of the embodiment of FIGURE 1.

FIGURE 3 is a perspective view of a modification of the invention.

Referring to the figures, the shaft 1 may be a control shaft of the typewhich is rotated a fraction of a turn in either direction to actuateswitches, potentiometers or other control devices for controllingmovement in an instrument or vehicle.

5 are fixedly connected to and spaced from the shaft 1.

3,356,357 Patented Dec. 5, 1967 A spring 6 is tightly wound to the shaft1 or otherwise fixedly connected to the shaft 1 and the ends of thespring extend past the pins 4 and 5 as illustrated in FIGURE 2, so thatif the shaft is rotated in either direction, the spring acts to restoreit to a neutral position.

The neutral position is determined by the adjustable stop screws 7 and 8and the ends of the spring 6 extend sufliciently far enough to come incontact with both adjustment stops when the shaft 1 is in neutralposition.

If the shaft is rotated clockwise, as shown in FIGURE 2, the pin 4 Willmove the spring in a clockwise direction and the portion 4, of thespring 6 will be moved from the end of the screw 7 against the springforce. Therefore, when the turning force is removed, the spring 6 willpress against the pin 4 and move the flange and shaft back to itsneutral position, that is until it comes in contact with the adjustablescrew 7.

Similarly, if the shaft 1 is moved counter-clockwise the spring 6 willbear on the pin 5 to return shaft 1 to its neutral position, when theturning force is removed.

The adjustable stop screws have relatively large heads to assure a goodcontact with the ends of the spring and they are easily adjustable torestore the shaft to neutral position. Lock nuts 7' and 8' arepreferably provided to lock the adjustable stop screws in properposition.

Therefore, even if the spring force changes due to aging or comesunequal for any reason or if a new spring is installed, the adjustmentmay be made easily to compensate for any error effect.

FIGURE 3 is a modification of the invention illustrating use of a leafspring 10. In this modification the pins 4' and 5' are mounted on theflange 2 and the leaf spring has a curvature which is adapted to fitaround the shaft 1. The leaf spring is designed so that it will fit intoposition between the shaft 1 and pins 4' and 5' and be held there by itsown spring force. The operation is the same as primarily described.

Therefore, the present invention provides a simple inexpensiveself-centering means for control shafts which is easily adjustable.

Many modifications may be made by those who desire to practice theinvention without departing from the scope thereof which is defined bythe following claims.

I claim:

1. Adjustable self-centering means for a shaft rotatably mounted in aframe comprising:

a pair of members fixedly connected to and spaced from said shaft,

a spring mounted on said shaft adjacent said members,

a pair of adjustable stops mounted in said frame and equally spacedoutwardly of said members, the ends of said springs extending outwardlypast said members and adapted to come into contact with said adjustablestops when said shaft is in neutral position so that when said shaft isrotated in either direction, one end portion of said spring will bearagainst one of said members in a direction to restore said shaft toneutral position, said neutral position being determined by the positionof said adjustment stops.

2. Apparatus as in claim 1 wherein said members are pins mounted in aflange fixedly connected to said shaft and said adjustable stop membersare screws.

3. Apparatus as in claim 1 wherein said spring is a leaf spring.

No references cited.

ARTHUR L. LA POINT, Primary Examiner. R. M. WOHLFARTH, AssistantExaminer.

1. ADJUSTABLE SELF-CENTERING MEANS FOR A SHAFT ROTATABLY MOUNTED IN AFRAME COMPRISING: A PAIR OF MEMBERS FIXEDLY CONNECTED TO AND SPACED FROMSAID SHAFT, A SPRING MOUNTED ON SAID SHAFT ADJACENT SAID MEMBERS, A PAIROF ADJUSTABLE STOPS MOUNTED IN SAID FRAME AND EQUALLY SPACED OUTWARDLYOF SAID MEMBERS, THE ENDS OF SAID SPRINGS EXTENDING OUTWARDLY PAST SAIDMEMBERS AND ADAPTED TO COME INTO CONTACT WITH SAID ADJUSTABLE STOPS WHENSAID SHAFT IS IN NEUTRAL POSITION SO THAT WHEN SAID SHAFT IS ROTATED INEITHER DIRECTION, ONE END PORTION OF SAID SPRING WILL BEAR AGAINST ONEOF SAID MEMBERS IN A DIRECTION TO RESTORE SAID SHAFT TO NEUTRALPOSITION, SAID NEUTRAL POSITION BEING DETERMINED BY THE POSITION OF SAIDADJUSTMENT STOPS.